It is desirable in the packaging industry to be able to load several items as a layer of items into a tray having a top opening (i.e. items can be loaded from above downwards onto the base of the tray to provide a layer of items that at least partially cover the upper surface of the base). It is also desirable to be able to load the tray with more than one layer of such items.
For example, in the food industry, it is well known to have a tray having multiple layers of cookies, each layer comprising several cookies.
To be able to facilitate the loading of the trays, several items are typically first accumulated together into a group and then loaded as a group into an open topped tray.
A known method of loading such trays provides a tray moving in a longitudinal direction on a tray conveyor brought into an adjacent position relative to an item loading conveyor also moving in the same longitudinal direction. If a tray is brought into close proximity to the group of items, the items can be transferred transversely from the moving item loading conveyor into the moving tray carried by the tray conveyor. One difficulty with this type of loading is that if the item conveyor and the carton conveyor continue to move at the same speed in the same horizontal and longitudinal direction, when the items are discharged into the tray transversely they will also move to some degree vertically as they enter the tray from above. Due to the combined transverse, longitudinal and vertical movement, items have a tendency to become improperly oriented when they reach the tray.
One known improved system for loading a tray, is to bring the trays carried on the tray conveyor to a stationary position for loading. The tray can then be loaded while stationary and then be moved again longitudinally by the tray conveyor once the loading has taken place. However, a problem with this method is that if reasonably fast speeds are maintained, to provide a high rate of tray loading, there is a significant acceleration of the tray out of the loading station once the tray has been filled. Depending upon the type of items involved, this can result in the items becoming improperly configured in the tray itself. Thus, this type of system has limits in terms of the type of items that can be loaded in this way and in terms of the maximum speeds and accelerations that can be imparted upon the loaded trays.
It is also known to employ robots having robot arms with end effectors configured for picking up several items at once and then placing them into trays. However, there is a limit to the speed at which robot arms can move. Also they are a relatively complex and expensive solution.
Accordingly, it is desirable to have an improved method and apparatus for loading trays having open tops with a plurality of items.